This application is based on Japanese Patent Application No. 2002-211219 filed on Jul. 19, 2002, the disclosure of which is incorporated herein by reference.
The present invention relates to an inside/outside air switching device having a rotary door for a vehicular air conditioning unit.
In recent years, it has been desired to reduce noise generated by a vehicular air conditioning unit. In response to the desire, for example, inside and outside air introduction ports of an inside/outside air switching device are enlarged so that an air intake resistance of a blower unit, which is provided downstream of the inside/outside air switching device, is reduced.
In the inside/outside air switching device, an inside/outside air switching door is moved against dynamic pressure of outside air during a vehicle running. With regard to the door for such inside/outside air switching device, a rotary door is proposed. The rotary door can be operated by a less power against dynamic pressure and can open and close the enlarged air introduction ports, as compared with a general plate like door.
The rotary door has a rotation shaft, a periphery wall rotating about the rotation shaft, and side plates connecting axial ends of the periphery wall and the rotation shaft. The rotary door is rotatably supported in a case of the inside/outside air switching device. The case has a separation wall between the inside air introduction port and the outside air introduction port. The rotary door is disposed such that the periphery wall passes through an inner peripheral side of the separation wall. Also, there is a clearance defined between the partition wall and the periphery wall to facilitate rotation of the door.
The rotary door generally has sealing members at its periphery to create seal between itself and the inside air introduction port and the outside air introduction port during an outside air mode and inside air mode, respectively. However, in an air mixing mode, the door is moved at a position that the door slightly opens the inside air introduction port and mainly opens the outside air port to partially mix inside air inside a passenger compartment with outside air outside the passenger compartment.
At this time, the sealing members separate from sealing surfaces formed on peripheries of the inside air introduction port and the outside air introduction port. Thus, the inside air introduction port communicates with the outside air introduction port through the clearance between the partition wall and the periphery wall. As a result, it is likely that rainwater, which has entered from the outside air introduction port, flows in the passenger compartment through the clearance.
The present invention is made in view of the foregoing matter and it is an object of the present invention to provide an inside/outside air switching device having a rotary door capable of restricting water such as rainwater from entering in a passenger compartment along a periphery wall of the rotary door.
According to an aspect of the present invention, an inside/outside air switching device for an air conditioning unit of a vehicle includes a case defining an air passage through which air flows, a rotary door rotatably supported in the case and a cover member. The case forms a first port through which inside air inside a compartment is introduced and a second port through which outside air outside the compartment is introduced. The rotary door selectively opens and closes the first port and the second port. The rotary door includes a rotation shaft, a periphery wall moved about a rotation shaft, and side walls connecting between axial ends of the periphery wall and the rotation shaft. In an air mixing mode, the rotary door is disposed such that the periphery wall projects toward the second port by a predetermined distance so that the door slightly opens the first port and mainly opens the second port. The cover member is disposed to cover a projected portion of the periphery wall.
Accordingly, the cover member restricts water such as rainwater from dropping on the projected portion of the periphery wall. Therefore, it is less likely that the water flows in the passenger compartment along the periphery wall. Preferably, the second port is located under an outside air intake port of a cowl of a vehicle and the cover member is disposed adjacent to the cowl.
According to another aspect of the present invention, an inside/outside air switching device for a vehicular air conditioning unit includes a case defining a first port and a second port, a rotary door rotatably supported in the case, and an elastic sealing member. The case has an intermediate wall between the first port and the second port, and the intermediate wall defines a sealing surface on a perimeter of the second port. The rotary door is disposed to selectively open and close the first port and the second port. The rotary door includes a rotation shaft, a periphery wall rotating about the rotation shaft, side walls connecting between axial ends of the periphery wall and the rotation shaft, and a sealing portion at an end of the periphery wall. The sealing portion is brought into contact with the sealing surface of the case when it fully opens the second port. The elastic sealing member is disposed to create seal between the intermediate wall and the periphery wall when the door partially opens the first port and mainly opens the second port in an air mixing mode.
Accordingly, the elastic sealing member restricts water from entering the compartment along the periphery wall in the air mixing mode. Further, it is less likely that outside air directly flows in the compartment through a clearance between the periphery wall and the intermediate wall in the air mixing mode.